A smart adjustable Inelastic Nuclear Interactions counter based on compact Arduino control system and readout

We realized an embedded system, easy to install and to calibrate, remote controlled and adjustable in order to equip an extracted beam line of a precise Inelastic Nuclear Interactions (INI) counter. The system made up of the Nuclear Interaction Detector (NID) and of a motorized, two arms, translation stage which allows precise positioning and scan of different inelastic nuclear scattering angles. The NID is based on twin small scintillators ($5 \times 10 \times 25$ mm$^3$ of BC-408), as nuclear interaction counters, every coupled with two Hamamatsu SiPMs (MPPC,multi-pixel photon counter), to get readout redundancy and to use coincidence strategy for minimizing the system noise. The signal readout is provided by Arduino Mega-based system, which makes available four pairs of bias voltage channel and analog readout channel for as many $3 \times 3$ mm$^2$ SiPMs. A constant fraction system enables getting fine timing coincidence both between scintillators and between beam's trigger signal and scintillators to minimize the fake counts on the radiative environment. Remote gap adjustment makes possible to set the nuclear scattering angle of measurement as well as to make an angular scan. The system was used as new nuclear interaction counter for the H8 telescope of the UA9 experiment. This CERN-SPS experiment aim to test the crystal assisted collimation for both protons and lead ion beam collimation in the LHC. The NID fulfill the precise measurements of nuclear interactions probability between crystal and particles in the various channeling regimes (channeling, volume reflection etc.).